There is an erasing apparatus for erasing the color of an image by making the color generated by a color material invisible so as to reuse a sheet.
The color erasing apparatus heats the visualized color material so as to reduce the effect of the color developing material to the color generation compound (dye precursor compound) which generates color under the effect of the color developing agent and release (erase) the color generation state.
In addition, as the sheet is not reused if the reuse times exceeds a given reuse times, a marking device is used to carry out marking indicating the reuse times on the color-erased sheet during the color erasing processing so that a user can know the reuse times. In most cases, the marking device is an optional device (individual addition device).